The time analysis of the solar neutrino interaction rate in Borexino is performed through signal processing techniques, applied to the time series of the total event rate in a fixed energy window. The energy estimator is the number of photo-electrons after an event position-dependent correction for the spherical geometry
(“geometry-normalized Npe”), see Ref. [1]}. To maximize the signal-to-background for solar neutrinos,
a region of interest (RoI) in the energy spectrum
is chosen according to the following Figure of Merit (FoM):
\(FoM\,(\Delta E) = \frac{R_S}{\sigma (R_{tot})},\) 
